Solar Hot Water Calculator

What savings can be made with an efficient shower head and tap aeration?

Calculate your answers here.

Solar Hot Water Savings Ideas

Replace a shower head for a water efficient one and Save 55% in water and associated heating costs.
Install tap aerators and Save 75% in water and associated heating costs.

Solar Hot Water Calculator

Calculate your yearly hot water consumption and hot water costs.
See what a different efficient shower heads and aerators can make.
Evaluate if solar hot water capital costs compare with 20+ years of hot water savings.Fill in the values in the top 3 tables.
Press Get Results button.
See you hot water annual costs and possible water efficiency savings.

Water Use

Consumption Guide: Open tap 20 l/min, 3 star shower head 9 l/min, aerator tap 5-7 l/min.
Time the filling of a known sized container for more accuracy.
Consider trying to keep showers to 4 minutes each.

Description

Time in minutes per daye.g. 10

Proportion Hot Water(0-1) e.g. 0.5

Normal use inlitres/minute

Efficient usein litres/minute

Shower

20 litres per minute

9 litres per minute

Hand washing / dish rinsing etc.

20 litres per minute

5 litres per minute

Water Use continued

Consider only using the dishwasher when full. Compare water use of a shower versus a bath.

Power Costs and Solar Power Available

Water and Energy Use Results

The power and cost calculations is based on a conventional electric storage water heater. Water efficient shower heads cost about $40, tap aerators cost about $10.
See how much savings can be made by their use in the short and long term. The return on investment should be good in most cases.
Solar hot water can save even more. The capital cost must be compared to the potential savings. Do you still use enough hot water to make a case for its installation?
Calculate all possible energy efficient activities and see which ones are easiest to implement and get the best return on investment.

Parameter

Normal Values

Water Efficient Values

Water Efficient Savings

Total Hot Water Use for day in litres.
This is useful for calculating hot water storage size needed.

litres

Total Hot Water Use for year in litres

litres

Hot water power consumption per year estimate (kWh) not including
reheating

kWh

Electricity hot water costs per year ($)

$$

Electricity hot water costs per 20 years ($)

$$

Potential local Solar Hot Water savings over 20 year (kWh)
Also Potential CO2 reduction in kilograms for coal electric power

kWh

Potential local Solar Hot Water savings over 20 year ($)

$$$$

Does the Solar Hot Water Calculator show you efficiency savings?

Solar Hot Water Configurations

Solar Hot Water Type

Advantages

Disadvantages

Solar Collector pre heating ($1000-$1500 AUD)

Can be used with existing hot water tanks. Cheap. Only requires a plumber.

Is not useful for reheating hot water.

Solar hot water with rooftop tank ($3000-$4000 AUD)

Single Unit on roof. Booster heater is built in.

Roof must be able to support weight when full of water.

Solar hot water split system ($4000-$6000 AUD)

Solar collector on roof, water tank on ground. Solar collector is modular and can be extended.

A small pump (~50 watts) is needed for water circulation. Power point is needed near tank for controller and pump.